in that config I will refer to the kernel as /__active/boot/vmlinux-linux ?

I guess in the fstab where you would specify a mount option for which subvolume to mount on boot

thomas.oster wrote:

But if I now want to load a rollback image with a different kernel in it's boot, how does it work?

Not quite sure what you mean here. If you snapshotted the subvolume that contains you /boot dir, then you can just specify a different subvolume to boot in fstab and it should work. First try to mount somewhere the subvolume you want to boot into to see what you have in there (you should see the whole tree). And of course have your live CD/USB ready in case you mess up.You also might want to review the wiki though it is quite outdated.

I have my root volume btrfs and the subvolume __active, aswell as the __snapshot directory with subvolume snapshots in between.For now I also have a /boot directory in the root volume and grub uses that, so I have to copy the current kernel from the __active-volume's boot directory after updates.

As I understand, I now have to install grub in a way, that it will read its config file from __active/boot (which is a directory in the __active subvolume) andin that config I will refer to the kernel as /__active/boot/vmlinux-linux ?

But if I now want to load a rollback image with a different kernel in it's boot, how does it work?

]]>https://bbs.archlinux.org/profile.php?id=684542013-02-17T17:03:43Zhttps://bbs.archlinux.org/viewtopic.php?pid=1233269#p1233269archphil, jfyi some long time ago when I had little RAM I created a unit file for systemd to mount a swapfile. It can be done only via loop device in btrfs for as far as I know. It won't be exceptionally fast, but quite workable.

First, you need to create a swap file as usual and format it - in the following case /var/myswaparea/myswapfile. I don't know why you want it in a subvolume, but you certainly can.

Then you just install this service file as usual in systemd.This unit file *assumes* /dev/loop0 to be free on boot.

]]>https://bbs.archlinux.org/profile.php?id=496372013-01-31T16:17:40Zhttps://bbs.archlinux.org/viewtopic.php?pid=1225244#p1225244I installed with three subvolumes, one for root, one for boot and one for home. I mounted boot and home inside the appropriate directories of root. Once made, the installation is the same as the wiki. No need for a special guide. Sorry aya but you made a too complicated one i think.Maybe the new kernel made it easaier, I worked with kernel 3.7.2 on a virtual machine.Juste have to leave 1Mo unpartionned at the beginning for grub.Last thing for me is to find a way to create a swap file on another subvolume and the btrfs would be done.]]>https://bbs.archlinux.org/profile.php?id=677202013-01-25T14:00:54Zhttps://bbs.archlinux.org/viewtopic.php?pid=1222358#p1222358Thank you aya. I succeeded with your guide in a virtual machine, but not on my laptop, due to other issues.]]>https://bbs.archlinux.org/profile.php?id=518552013-01-03T21:21:04Zhttps://bbs.archlinux.org/viewtopic.php?pid=1213508#p1213508igoyak, some time ago I made a guide, maybe it will help you.Since systemd is now default, some parts of it, especially about the packages to be installed, would not apply, but the btrfs parts should still be valid.]]>https://bbs.archlinux.org/profile.php?id=496372013-01-03T14:34:00Zhttps://bbs.archlinux.org/viewtopic.php?pid=1213332#p1213332helloworld1, could you outline the steps you took to make it work? Or link to a guide that does?]]>https://bbs.archlinux.org/profile.php?id=518552013-01-03T14:18:51Zhttps://bbs.archlinux.org/viewtopic.php?pid=1213324#p1213324HiHow you dealt with"error: grub filesystem doesn't support blocklists"?]]>https://bbs.archlinux.org/profile.php?id=496372012-07-20T15:55:23Zhttps://bbs.archlinux.org/viewtopic.php?pid=1133400#p1133400Here you go.

]]>https://bbs.archlinux.org/profile.php?id=450582012-07-16T21:40:30Zhttps://bbs.archlinux.org/viewtopic.php?pid=1130983#p1130983ok ok that looks promising ... just because i've seen btrfs mount a directory in the past (IIRC internally it just does a -- bind mount), then hose itself soon after, can you please list your subvolumes with:

# btrfs sub list /

... and your /:

# ls -al /

... from within the booted, running system? if that looks correct, i'll be convinced, and will allocate time toward this endeavor :-)

Seeming GRUB2 (I am using grub 2.0 rc1) supports BTRFS subvolume, but I couldn't find any guide about it.It takes me almost a day to successfully installed. Most of the time I tried to figure out how deal with grub-install's error "error: grub filesystem doesn't support blocklist". But otherwise, it is pretty straightforward. Run grub-mkconfig and the generated grub.cfg is working.

yay :-)

you are certain it's in a subvol and not the top-level volume, correct? i've been thinking about this lately and if what you state is true then -- after several years of false starts and wishful thinking -- i can finally implement kernel-level rollback support in mkinitcpio-btrfs ... hooray! virtually impossible to bork your system at that point.

the hook has stagnated for a *very* long time while i let the tools mature (reimpl is annoying; time is precious) ... i'll do some testing to verify said claims. thanks!

Yes, NO top-level volume, the /boot is in the /btrfs-root subvolume. I don't see anyone share successful story in the forum or wiki. So I just post here. I don't have time to write a guide but glad to answer questions and hopefully someone can write a wiki about it.Here is my mount

Seeming GRUB2 (I am using grub 2.0 rc1) supports BTRFS subvolume, but I couldn't find any guide about it.It takes me almost a day to successfully installed. Most of the time I tried to figure out how deal with grub-install's error "error: grub filesystem doesn't support blocklist". But otherwise, it is pretty straightforward. Run grub-mkconfig and the generated grub.cfg is working.

yay :-)

you are certain it's in a subvol and not the top-level volume, correct? i've been thinking about this lately and if what you state is true then -- after several years of false starts and wishful thinking -- i can finally implement kernel-level rollback support in mkinitcpio-btrfs ... hooray! virtually impossible to bork your system at that point.

the hook has stagnated for a *very* long time while i let the tools mature (reimpl is annoying; time is precious) ... i'll do some testing to verify said claims. thanks!

]]>https://bbs.archlinux.org/profile.php?id=298172012-07-10T09:17:22Zhttps://bbs.archlinux.org/viewtopic.php?pid=1127525#p1127525May I ask, What is your question here?]]>https://bbs.archlinux.org/profile.php?id=530132012-07-04T20:41:49Zhttps://bbs.archlinux.org/viewtopic.php?pid=1125355#p1125355Seeming GRUB2 (I am using grub 2.0 rc1) supports BTRFS subvolume, but I couldn't find any guide about it.It takes me almost a day to successfully installed. Most of the time I tried to figure out how deal with grub-install's error "error: grub filesystem doesn't support blocklist". But otherwise, it is pretty straightforward. Run grub-mkconfig and the generated grub.cfg is working.]]>https://bbs.archlinux.org/profile.php?id=450582012-07-04T16:38:54Zhttps://bbs.archlinux.org/viewtopic.php?pid=1125250#p1125250